JPS62267203A - Insecticide - Google Patents

Abstract

PURPOSE:To provide an insecticide produced by compounding a pyrethroid compound with another compound at a specific ratio, having low toxicity and improved solubility in water, containing the pyrethroid compound in high stability and resistant to the lowering of insecticidal activity of the active component caused by long-term storage of the insecticide. CONSTITUTION:The objective insecticide is a clathrate compound produced by clathrating (A) 0.1-10wt% pyrethroid compound (e.g. resmethrin, allethrin, etc.) with (B) 1/2-20 times weight (based on the component A) of a methylated cyclodextrin of formula (n is 6-9; at least one of the 3n A groups is CH3 and the others are H) capable of forming a clathrate compound (e.g. a methylated beta-cyclodextrin having a weight-average ether substitution degree of 8.0-11.0 and containing >=50wt% compound having an ether substitution degree of 8-11. An aqueous solution containing >=10wt% said insecticide can be produced at room temperature. EFFECT:It is applicable for rapid and long-acting treatment and utilizable to a wide variety of insecticides such as wettable powder, solution, emulsifiable concentrate, aerosol, fumigant, etc., as well as powder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an insecticide, and more particularly to an insecticide containing a pyrethroid compound and a specific methylated cyclodextrin and having superior stability.

[Conventional technology]

Conventionally, pyrethroid compounds have shown high insecticidal effects against sanitary pests such as mosquitoes, insects, and cockroaches, but their toxicity to humans and livestock is significantly lower than that of other insecticides, so they are widely used as general household insecticides. It is being

Such pyrethroid compounds have poor stability against heat, light, and even oxygen in the air. For this reason, when pyrethroid compounds are used as insecticides, they have drawbacks such as lack of stability in formulations and lack of sustainability of effects when actually used.

Furthermore, pyrethroid compounds themselves dissolve and mix in oily bases such as kerosene, but hardly dissolve in water. For this reason, pyrethroid insecticides were used in the form of oils or emulsions, and were subject to hazardous substance regulations, which meant that there was a time limit for their storage. Of these disadvantages, the former is mainly used only in the summer and is rarely used in the winter, so it may be stored for a long time in a W warehouse, etc., or the residual value may be used to exterminate small insects such as cockroaches. It is fatal if left untreated. For this reason, pyrethroid compounds can be adsorbed to mineral fine powder such as Merck, or they can be included in cyclodextrins,
BHA-? Attempts have been made to stabilize the compound itself by adding an antioxidant such as BHT or by introducing a halogen into the pyrethroid compound.

[Problem that the invention seeks to solve]

However, pyrethroid compounds obtained by adsorption to talc or inclusion in cyclodextrin are powders that are insoluble in water or oily bases, which severely limits the dosage form when formulating them. There was a point. Furthermore, the addition of antioxidants cannot be said to be sufficiently effective, and although the stability of the pyrethroid compounds themselves has been improved by the introduction of halogens, the original features of pyrethroid compounds such as low toxicity and environmental pollution, and even resistance to Issues such as gender are in the spotlight. In addition, in an attempt to exclude the application of the formulation as a hazardous substance, no studies have been conducted on the dissolution of pyrethroid compounds in water other than emulsification using surfactants.

Therefore, there is a strong desire for the emergence of insecticides that can be widely applied in preparations that are highly stable and easily soluble in water, taking advantage of the characteristics of pyrethroid compounds that are effective and have low toxicity to human life. Ta.

[Means for solving problems]

As a result of intensive research to develop an insecticide that satisfies the above requirements, the present inventors have found that by treating a pyrethroid compound in advance with a specific methylated cyclodextrin and using it in an insecticide, the stability can be improved. They discovered that the solubility in water etc. was improved and completed the present invention.

That is, the present invention comprises (A) o, x to 10 times more by weight of a pyrethroid compound, and (B) y2 to 20 times more by weight of general formula (I) (wherein, n is a number from 6 to 9). and among the 3n A's, at least one represents a methyl group and the remainder represents a hydrogen atom). .

The pyrethroid compounds of component (4), which are the active ingredients of the insecticide of the present invention, include only pyrethrin, which is the active ingredient of pyrethrum, and esters of di-chrysanthemum acid and di-chrysanthemum acid, which have a similar chemical structure. However, these derivatives are mentioned,
Specific examples include pyrethrin, allethrin, phenothrin, floparthrin, flamethrin, resmethrin, permethrin, and phenothrin.

It is known that IJ (formerly known as Siphrobukis) forms clathrate compounds with various substances, and is said to also form clathrate compounds with pyrethroid compounds. JP-A-49-71135 discloses a method of stabilizing pyrethroid compounds using this principle. However, the clathrate compounds formed in such inventions are insoluble in oily bases or water commonly used for insecticides;
It can only be used as powder preparations such as powders and irrigation agents.

In particular, the fact that pyrethroid compounds cannot be used as liquid agents in general household insecticides, in which pyrethroid compounds are frequently used, is a significant drawback.

Similarly to cyclodextrin, methylated cyclodextrin (I) as component (B) used in the present invention has the ability to form clathrate compounds with various substances. Furthermore, this methylated cyclodextrin (I) has a good inclusion rate, and the resulting clathrate compound forms an aqueous solution of 10% by weight or more at room temperature, so it has a wide range of applications as an insecticide. It is.

Among the methylated cyclodextrins of general formula (I), n
is 6, methylated α-cyclodextrin, n is 7
The one with n=8 is called methylated β-cyclodextrin, the one with n=8 is called methylated r-cyclodextrin, and the one with n=9 is called methylated-monocyclodextrin, and all of these have clathrate-forming properties. shows.

Methylated cyclodextrin (I) is produced by methylating cyclodextrin according to a conventional method.

When cyclodextrin is methylated using a methylating agent such as dimethyl sulfate according to a conventional method, a mixture is obtained in which the hydroxyl groups of glucose residues are methylated in the order of 6-, 2-, and 3-positions.

In the present invention, it is sufficient that at least one of the 31 A's in general formula (I) is a methyl group, but preferably, the weight average degree of ether substitution is 8.0 to 11.0, Methylated β-cyclodextrin containing 50% by weight or more of 8-11 polydextrin is preferred.

Here, the degree of ether substitution refers to the number of methyl groups introduced per β-cyclodextrin molecule, and in a mixture containing 28 or more methylated β-cyclodextrins with different degrees of ether substitution, each degree of ether substitution and each The weight average degree of ether substitution is calculated based on the weight percent of the components.

The amount of pyrethroid compound added to the insecticide of the present invention is 0.
01 to 10 weight. In addition, the weight ratio of methylated cyclodextrin (I) to the pyrethroid compound is 1/1.
It is used in an amount of 2 to 20 times, preferably 1 to 10 times. Even if methylated cyclodextrin (I) is added in an amount less than % by weight of the pyrethroid compound, there is almost no effect on increasing stability, and even if it is used in an amount exceeding 20 times, no further stability is observed. No enhancement was observed.

The method for producing the insecticide of the present invention is carried out by blending the above two components, but in order to sufficiently incorporate the pyrethroid compound into the methylated cyclodextrin, the pyrethroid compound must be treated with the methylated cyclodextrin in advance. It is preferable to leave it there.

Methods for treating pyrethroid compounds with methylated cyclodextrin include a saturated aqueous solution method in which a pyrethroid compound is added to a saturated aqueous suspension of methylated cyclodextrin, and a saturated aqueous solution method in which a pyrethroid compound is added to a saturated aqueous suspension of methylated cyclodextrin. A kneading method is adopted in which the mixture is mixed with water using a kneader or the like.

The insecticide according to the present invention can be used not only as a powder and an irrigation agent, but also as a solubilizer in water, etc., so it can be used as a variety of liquids, emulsions, and aerosols. It can also be used as a fumigant,
Honkawa can be used as a smoking agent. In producing these preparations, various additives used in conventional insecticide preparations can also be added. That is, synergists such as piveronyl ptoxide, antioxidants such as BHT and BHA, ultraviolet absorbers, and surfactants can be used as appropriate.

[Effect]

The insecticide of the present invention enhances the stability of pyrethroid compounds and also solubilizes them in solvents such as water, so that they can be applied to various preparations. The mechanism of action is presumed to be that the pyrethroid compound is included in methylated cyclodextrin (I), thereby preventing decomposition due to oxidation caused by heat, light, or oxygen in the air. Since methylated cyclodextrin has higher solubility in water than conventional cyclodextrin, it is thought that a compound containing a pyrethroid compound will dissolve in water and the like.

〔Effect of the invention〕

The insecticide of the present invention stabilizes a low-toxicity and effective pyrethroid compound and expands its application to various sandalwood preparations, making it possible to prevent the insecticidal power of the active ingredient from decreasing due to long-term storage of the preparation. It became.

In addition, pyrethroid compounds have conventionally been excellent in quick-acting properties but lacked residual properties, but with the present invention, they can also be applied by a method called residual treatment, which is expected to have residual effects. Further, conventional cyclodextrin inclusion compounds have been limited to use as powders, but the insecticide of the present invention has the advantage that it can be used not only in powders but also in various liquids.

〔Example〕

Next, the present invention will be explained in detail with reference to Examples.

Example 25 m-% of lusmethrin was treated with methylated β-cyclodextrin (average degree of ether substitution: 94) in 75 molar quantities to obtain the clathrate compound C (25 m-% as resmethrin). To 5v of this material was added 95F of diatom, and the mixture was sufficiently stirred and mixed to obtain a powder.

Example 2 Phthalthrin 1.0 wt'J1% was pre-treated with 3.0 wt% methylated β-7 clodextrin (weight average degree of ether substitution 9.0), water was added to make a total volume of 100 ml, A liquid preparation was obtained.

Example 3 2.0% by weight of allethrin 0.5% methylated β-
Cyclodextrin (heavy paper average degree of ether substitution 109)
Pre-processed with 30% starch and further added 67.5% starch
jk% of water was added and mixed well to obtain poisoned bait.

Example 4 Methylated β-cyclodextrin (weight average degree of ether substitution 8.0) 75% by weight of allethrin
clathrate compound (25% by weight as allethrin)
I got it. This thing has 2 pre-chi, Cinepirin 5002.0
The mixture was uniformly mixed with 96 volumes of a mosquito coil base consisting of pyrethrum extract powder, cedar powder, starch, etc. to obtain a mosquito coil according to a known method.

Example 5 A liquid preparation using the pyrethroid compound proboscis clathrate compound shown below was produced as a prototype, and after being stored at 40° C. or room temperature (RT) for a certain period of time, the appearance and residual amount of the active ingredient were measured. The results are shown in Table 1. The methylated β-cyclodextrin used had an average N content and degree of ether substitution of 9.0.

(Composition 1) Allethrin 1
．． 0-fold f-thimethylated β-cyclodextrin
3.0 water 96. O
(Composition 2) Resmethrin 1
．． 0% by weight methylated β-cyclodextrin
3.0 Water 96.0 (Composition 3) Propalthrin 1.0% by weight Methylated β-cyclotextrin 3.0 Water
96.0 (control 1
) Allethrin 1.0% by weight
β-cyclodextrin 3.0 water
96.0 (Control 2) Resmethrin 1.0% by weight β-cyclodextrin 3.0 Water
96.0 (Control 3) Propalthrin 1.0% by weight β-cyclodextrin 3.0 Water
96.0 (Control 4) Allethrin
1.0% water by weight
99.0 (Control 5) Resmethrin
1.0% water by weight
99.01 light 6) Proparthrin 1.0% water by weight
99. Margin below O Example 6 Composition 2 of Example 5 and control material 5 were produced as a trial, and 1Ox10m
IIR1tI4 was applied to the decorative board of 2000 and air-dried at room temperature.

After storing it at room temperature for two weeks, apply butter to the inside of a glass ring with a height of 5 cm and an inner diameter of 9 m, and place it on the decorative board,
Ten female German cockroaches were released and the number of knockdowns was measured over time. The obtained product of the present invention of Example 5 (
Composition 2) did not need to be shaken before treatment and showed sufficient shelf life.

that's all Procedural amendment (voluntary) June 171, 1985”

Claims (1)

[Claims] 1. (A) 0.1 to 10% by weight of a pyrethroid compound and (B) 1/2 to 20 times the weight of (A) of the general formula (I) ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (In the formula, n represents a number from 6 to 9, at least one of the 3n A's represents a methyl group, and the rest represent hydrogen atoms.) An insecticide characterized by containing a methylated cyclodextrin represented by: 2. The methylated cyclodextrin has a weight average degree of ether substitution of 8.0 to 11.0 and a degree of ether substitution of 8 to 1.
2. The insecticide according to claim 1, wherein the insecticide is a methylated β-cyclodextrin containing 50% by weight or more of 1.